The bitcoinjs-lib npm package is a library for Bitcoin-related operations in JavaScript. It provides tools for creating, signing, and verifying Bitcoin transactions, as well as generating and managing Bitcoin addresses and keys.

What are bitcoinjs-lib's main functionalities?

Generate a Bitcoin Address

This feature allows you to generate a new Bitcoin address. The code creates a random key pair and derives a Bitcoin address from the public key.

const bitcoin = require('bitcoinjs-lib');
const keyPair = bitcoin.ECPair.makeRandom();
const { address } = bitcoin.payments.p2pkh({ pubkey: keyPair.publicKey });
console.log(address);

Create a Bitcoin Transaction

This feature allows you to create a Bitcoin transaction. The code builds a transaction by adding inputs and outputs, and then signs it with the private key.

const bitcoin = require('bitcoinjs-lib');
const keyPair = bitcoin.ECPair.fromWIF('your-private-key');
const txb = new bitcoin.TransactionBuilder();
txb.addInput('previous-txid', 0); // Add input (previous transaction)
txb.addOutput('recipient-address', 100000); // Add output (recipient address and amount in satoshis)
txb.sign(0, keyPair); // Sign the transaction
const tx = txb.build().toHex();
console.log(tx);

Verify a Bitcoin Transaction

This feature allows you to verify a Bitcoin transaction. The code parses a transaction from its hexadecimal representation and checks if all inputs have valid scripts.

const bitcoin = require('bitcoinjs-lib');
const tx = bitcoin.Transaction.fromHex('transaction-hex');
const txb = bitcoin.TransactionBuilder.fromTransaction(tx);
const isValid = txb.inputs.every(input => input.script && input.script.length > 0);
console.log(isValid);

Other packages similar to bitcoinjs-lib

Changelog

Source

5.1.7

fixed

Fixed Transaction class Output interface typing for TypeScript (#1506)
Add weight() to Block class, add optional includeWitness arg to Transaction byteLength method (#1515)
Match the old TransactionBuilder behavior of allowing for multiple instances of the same pubkey to be in a p2ms script for PSBT (#1519)

added

Allow the API consumer to pass in the finalizer functions to allow for any type of transaction to be finalized. It places the most crucial part of transaction construction on the consumer, and should be used with caution. (#1491)

Readme

Source

BitcoinJS (bitcoinjs-lib)

A javascript Bitcoin library for node.js and browsers. Written in TypeScript, but committing the JS files to verify.

Released under the terms of the MIT LICENSE.

Should I use this in production?

If you are thinking of using the master branch of this library in production, stop. Master is not stable; it is our development branch, and only tagged releases may be classified as stable.

Can I trust this code?

Don't trust. Verify.

We recommend every user of this library and the bitcoinjs ecosystem audit and verify any underlying code for its validity and suitability, including reviewing any and all of your project's dependencies.

Mistakes and bugs happen, but with your help in resolving and reporting issues, together we can produce open source software that is:

Easy to audit and verify,
Tested, with test coverage >95%,
Advanced and feature rich,
Standardized, using prettier and Node Buffer's throughout, and
Friendly, with a strong and helpful community, ready to answer questions.

Documentation

Presently, we do not have any formal documentation other than our examples, please ask for help if our examples aren't enough to guide you.

Installation

npm install bitcoinjs-lib

Typically we support the Node Maintenance LTS version. If in doubt, see the .travis.yml for what versions are used by our continuous integration tests.

WARNING: We presently don't provide any tooling to verify that the release on npm matches GitHub. As such, you should verify anything downloaded by npm against your own verified copy.

Usage

Crypto is hard.

When working with private keys, the random number generator is fundamentally one of the most important parts of any software you write. For random number generation, we default to the randombytes module, which uses window.crypto.getRandomValues in the browser, or Node js' crypto.randomBytes, depending on your build system. Although this default is ~OK, there is no simple way to detect if the underlying RNG provided is good enough, or if it is catastrophically bad. You should always verify this yourself to your own standards.

This library uses tiny-secp256k1, which uses RFC6979 to help prevent k re-use and exploitation. Unfortunately, this isn't a silver bullet. Often, Javascript itself is working against us by bypassing these counter-measures.

Problems in Buffer (UInt8Array), for example, can trivially result in catastrophic fund loss without any warning. It can do this through undermining your random number generation, accidentally producing a duplicate k value, sending Bitcoin to a malformed output script, or any of a million different ways. Running tests in your target environment is important and a recommended step to verify continuously.

Finally, adhere to best practice. We are not an authorative source of best practice, but, at the very least:

Don't re-use addresses.
Don't share BIP32 extended public keys ('xpubs'). They are a liability, and it only takes 1 misplaced private key (or a buggy implementation!) and you are vulnerable to catastrophic fund loss.
Don't use Math.random - in any way - don't.
Enforce that users always verify (manually) a freshly-decoded human-readable version of their intended transaction before broadcast.
Don't ask users to generate mnemonics, or 'brain wallets', humans are terrible random number generators.
Lastly, if you can, use Typescript or similar.

Browser

The recommended method of using bitcoinjs-lib in your browser is through Browserify. If you're familiar with how to use browserify, ignore this and carry on, otherwise, it is recommended to read the tutorial at https://browserify.org/.

NOTE: We use Node Maintenance LTS features, if you need strict ES5, use --transform babelify in conjunction with your browserify step (using an es2015 preset).

WARNING: iOS devices have problems, use atleast buffer@5.0.5 or greater, and enforce the test suites (for Buffer, and any other dependency) pass before use.

Typescript or VSCode users

Type declarations for Typescript are included in this library. Normal installation should include all the needed type information.

Examples

The below examples are implemented as integration tests, they should be very easy to understand. Otherwise, pull requests are appreciated. Some examples interact (via HTTPS) with a 3rd Party Blockchain Provider (3PBP).

If you have a use case that you feel could be listed here, please ask for it!

Contributing

See CONTRIBUTING.md.

Running the test suite

npm test
npm run-script coverage

Complementing Libraries

BIP21 - A BIP21 compatible URL encoding library
BIP38 - Passphrase-protected private keys
BIP39 - Mnemonic generation for deterministic keys
BIP32-Utils - A set of utilities for working with BIP32
BIP66 - Strict DER signature decoding
BIP68 - Relative lock-time encoding library
BIP69 - Lexicographical Indexing of Transaction Inputs and Outputs
Base58 - Base58 encoding/decoding
Base58 Check - Base58 check encoding/decoding
Bech32 - A BIP173 compliant Bech32 encoding library
coinselect - A fee-optimizing, transaction input selection module for bitcoinjs-lib.
merkle-lib - A performance conscious library for merkle root and tree calculations.
minimaldata - A module to check bitcoin policy: SCRIPT_VERIFY_MINIMALDATA

Alternatives

LICENSE MIT

Keywords

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Last updated on 06 Jan 2020

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Install

bitcoinjs-lib